Switchboard lamp cartridge plug

ABSTRACT

This invention provides a plug or cartridge assembly wherein a heat sensitive Light Emitting Diode (LED), and ballast resistor are part of an assembly, longitudinally spaced along the assembly so that when mounted in a panel aperture, the LED is at one (front) face of the panel and ballast beyond the other (or rear) face of the panel. The ballast is so mounted as to be accessible to atmosphere at the rear of the panel. The entire assembly is readily insertable into or removable from a panel.

Unlted States Patent [191 [111 ,818,486 Bailey June 18, 1974 SWITCHBOARDLAMP CARTRIDGE PLUG Primary Examiner-Harold l. Pitts 75 Inventor: JamesR. Bailey, Chicago, in. Kahn 73 Assi nee: Switchcraft Inc. Chic 0, I11.I l 1 g ag 57 ABSTRACT [22] Filed: May 7, 1973 ThlS invention provides aplug or cartridge assembly PP No: 357,932 wherein a heat sensitive LightEmitting Diode (LED),

' and ballast resistor are part of an assembly, longitudi- 52 U.s. Cl.340/381 R, 340/166 R Speeed along the assembly 80 that when mounted 51Int. Cl. G08b 5/36 in a Panel aperture, the LED is at one (hem) face of[58] Field of Search 340/381 R the Panel and ballast beyond the ether(er rear) face of the panel. The ballast is so mounted as to be acces-56] References Cited sible to atmosphere at the rear of the panel. Theentire assembly is readily insertable into or removable from a UNITEDSTATES PATENTS panel. 3,438,027 4/1969 Silvius 340/38] R 1 Claim, 4Drawing Figures I SWITCHBOARD LAMP CARTRIDGE PLUG INTRODUCTION use, theinvention is particularly suitable for telephone boards or othercommunication system boards having a large number of sockets. While atelephone switchboard useslow power indicating lamps, the large numberof such lamps distributed over a board creates a serious heat problem.For the most part, a switchboard or panel generally includes as asupporting element an extensive panel or board of synthetic plastichaving a large number of recesses or openings in which are disposedsignal lamps and sockets for accommodating plugs or switches forconnecting or disconnecting individual circuits as required. Examples ofsuch panels are disclosed in prior US. Pat. No. 3,597,866 granted Aug.l0, l9'7l and US. Pat. No. 3,61 l,360 granted Oct. 5, 1971. In manyinstances such signal lamps may be on for long periods of time. Thelamps must be visible from the front of the panel.

Within recent years there have been introduced so called SOLID STATELAMPS. Such lamps are lightemitting diodes having, for example, at leastone electrode of such material as Gallium Phosphide, adapted to emitlight. These lamps are adversely affected by heat. The light emission isobtained by electroluminescence from a diode during electriccurrentconduction. Such diodes are high efficiency, physically tiny devices,each having two wire leads, usually gold plated. Such light emittingdiodes (LED), like all electron discharge devices, require a ballastresistor for each lamp for current control and are used in circuitsenergized by direct voltages of definite values such as, for example, 24or 48 volts, widely used in telephone work.

Inasmuch as a solid state lamp requires its own ballast resistor, thevalue of which depends upon the magnitude of the voltage supply, it isdesirable to handle the lamp and its ballast as a unit and design theunit so that it becomes a cartridge plug for insertion into a jack in apanel board.

THE INVENTION GENERALLY The invention herein comprises a cartridge orplug assembly, of LED lamp together with its ballast, which is suitablyassembled in a holder so dimensioned and provided with suitable stiffwire leads so that the entire assembly may be handled as a plug whichcan be inserted into a conventional jack. The LED lamp is quitesensitive to heat. While the lamp itself is highly efficient andrequires little power, the ballast with which the lamp is associatedmust dissipate, by comparison, a substantial amount of heat energy.Because of this, the plug assembly is so constructed as to promote readyaccess of atmosphere to the interior of the assembly.

The plug assembly or cartridge itself is constructed to have tworearwardly extending stiff leads which are adapted to function orcooperate with jack contact blades carried by the panel board. Thus, theplug assembly may be readily inserted into or removed from a panel boardin the event that a lamp must be replaced. As a rule the arrangement issuch that a complete plug assembly consisting of lamp and ballastresistor and stiff leads are treated as a unit which is expendable andreplaceable conveniently.

THE DRAWINGS In order that the invention may be understood it will beexplained in conjunction with the drawings wherein:

' within a panel board, the scale of the drawing being much larger thanthe actual physical size of the item;

FIG. 2 is a view similar to FIG. 1 but showing a longitudinal section ofthe plug unit and also showing the spring contacts of a jack with whichthe rearwardly extending leads of the plug unit cooperate;

FIG. 3 is a transverse section along line 33 of FIG. 2;

FIG. 4 is a view of a portion of a panel in which the new plug units maybe carried.

DESCRIPTION OF THE PREFERRED SPECIES The panel board upon which theembodiment of the invention is adapted to be carried may consist of anyconventional board having a plurality of recesses or openingstherethrough disposed along lines, for exam ple, as shown in the issuedpatents previously identifled. As an example, a panel board may be ofBakelite or other rigid insulating plastic material having a thicknessof the general order of about one-fourth of threeeighths of an inch andhaving at least one or more rows of circular apertures therethrough,each one of which may be about one-fourth of an inch in diameter withadjacent apertures being suitably spaced from each other. Above eachline of apertures on a panel board, there may be means for accommodatingthe mounting of indicating or labeling strips to identify eachparticular receptacle or aperture. A panel board as a rule is rigidlysupported in a frame. Sometimes a large number of rows of apertures aredisposed in one panel board or one insulating strip may have anindividual line of apertures and is carried in a metal frame with spacedstrips to make up a complete switchboard panel as suggested in FIG. 4.

The rear face of a panel board usually has means for rigidly bolting ajack for each panel aperture, the jack extending rearwardlyperpendicular to the face of the panel. As an example, a panel strip ofinsulating material having a thickness of substantially three-eighths ofan inch may carry jacks having a length of something over 2 inchesextending rearwardly from the rear face of the panel strip. Inasmuch aspanel strips and panel boards are well known and widely used, no furtherdescription thereof is deemed necessary.

DESCRIPTION OF THE PLUG ASSEMBLY EMBODYING THE INVENTION LED lamp 10 hasa generally cylindrical body with enlarged head 11, both being of brassor other conducting metal. Enlarged portion 11 functions as a bezel inwhich is disposed, as by cementing, lens 12 consisting of transparent ortranslucent plastic. Lamp 10 comes with leads l3 and 14, preferably ofcopper and may have a thin plating of gold thereover. As an example, thebody of LED lamp 10 is cylindrical and has a diameter of 0.07 inches anda length of about 0.07 inches. The lens has a diameter of substantiallyI/IO inches. Wire lead I3 is the anode lead and has a diameter of 0.025inches while wire I4 is a cathode lead having it diameter of about 0.020inches. To prevent short circuiting, one of the wires, here shown as 14,is covered with insulating tubing 15. The lamp is disposed within moldedinsulating cap 16 having beveled front portion 17 provided with annularshoulder 18. The body of cap 16 continues rearwardly as sleeve 20 whoseinner surface 21 is large enough so that wire leads 13 and 14 may liewithin sleeve portion 20. To maintain the lamp and its leads firmlywithin cap 16, interior 23 of sleeve portion 20 may be filled withpotting compound used in transformers and other electrical devices forinsulation as well as for anchorage. Outer surface 24 of sleeve portion20 is cylindrical and is shaped to provide small step 25 leading to neckportion 25a which extends to annular portion 18.

Cap 16 is preferably of molded insulating plastic with outer surface 24of sleeve portion 20 adapted to fit snugly within housing 26. Housing 26is of molded insulating plastic and has a generally cylindrical innersurface adapted to fit over outer cylindrical surface 24 of the cap.Housing 26 has forward end 27 bevelled at 28 to provide annular portion29. Housing 26 has sleevelike portion 30 whose outer surface iscylindrical and is adapted to fit snugly within cylindrical aperture 31of panel board 32. Housing sleeve portion 26 has edge portion 30aextending between the outer cylindrical sleeve portion 30 and shoulder33 of the bevelled forward edge. Housing sleeve portion 26 is cementedto outer sleeve portion 24 of the cap. Any suitable cement, such asepoxy resin, may be used. Housing por' tion 26 however fits snuglywithin aperture 31 through the panel board and is adapted to be readilyinserted into or removed from the panel, as a plug or cartridge.

Housing portion 26 extends rearwardly to provide generally cylindricalelongated support portion 36 having a number of longitudinal windows 37to leave support fingers 38 and 39. The region within support portion 36between the fingers is long enough and large enough to accommodate oneor two ballast resistors 40 and 41. In some instances, only one resistoris needed. Each resistor has a low power rating usually about onehalfwatt and a suitable valve. Each resistor has leads 40a and 41a whichnormally extends forwardly of the resistor and is spot-welded to lampleads 13 and 14. Resistors 40 and 41 have rearwardly extending leads 40band 41b if two resistors are used. in the event that only one resistoris needed for a lamp combination, the original lead (13 or 14 as thecase may be) is extended rearwardly for the necessary distance. Rearleads 40b and 41b (if two separate leads are necessary) are preferablythick enough and stiff enough to function as contact pins.

Thus for example, if resistor 41 is unnecessary, lead 14 of the lamp isextended rearwardly as lead 41b. The two rearwardly extending leads passthrough suitable passages in rear end portion 45 of the housing, saidleads being adapted to fit snugly in such passages to be supportedthereby. Rear end portion 45 of the housing has substantial thicknessalong the length of the housing so that good mechanical support isprovided for the leads. Jack support bracket 46 carries metal jackspring blade contacts 48 and 49 of conventional shape as shown.Insulating blade 50 having forwardly tapering portion 51 provides asupport for jack contact spring blades 48 and 49 against which suchcontact spring blades can rest. Due to the shape of the forward ends ofcontact springs 48 and 49, it is obvious that the rear lead pin portions40b and 41b, suitably spaced apart from each other, can engage the twocontact spring blades and force them open to slip between the springcontact and the insulating blade.

lnasmuch as the lamp assembly is replaced infrequently, the pin-shapedcontact leads 40b and 41b can be just stiff enough so that an assemblycan be pushed in as shown in H0. 2. Annular shoulder 33 will restagainst the front face of panel 32 and limit the inward travel of theplug cartridge assembly. The entire assembly can be removed by grippingthe forward end of housing 26 and withdrawing the assembly.

The light emitting lamp is at the front of the entire plug assembly andis normally well ventilated. ln back of the panel, the various ballastresistors will be adequately ventilated, either natural or forced, andwill normally be far enough from the lamps so that the possibility of alamp being subjected to undesirable temperature conditions is quiteremote. The housing part of the entire assembly is part of a plugconstruction where the ballast resistor (or resistors) is spacedrearwardly of the front or diode end of the assembly sufficiently sothat for any normal panel thickness, the diode light emitting portionwill be at one (front) face of the panel and the ballast (or ballasts)will be rearwardly of the panel other (rear) face so that the ballastswill be in air for heat dissipation.

An individual jack includes a mounting support portion 55 adapted to lieagainst the rear panel face and adapted to be bolted to the panel rearface by bolt 56. In this instance, the jack mounting support is ofmolded plastic and has side webs 57. Other jacks may have a metal angleiron, a long leg supporting the jack compo nents and a short legfunctioning as a fastening part, similar to portion 55. Any kind of jackmay be used for cooperation with the plug assembly described before.

What is claimed is:

l. A lamp cartridge plug for switchboards comprising a light emittingdiode having a pair of leads, an insulating cap for supporting saiddiode, said cap being sleeveshaped with a light emitting part of saiddiode disposed at a front cap end for external viewing, said diode leadsextending from the rear cap end, a cartridge housing of molded,non-metallic material, said housing having a front sleeve portiondisposed about the cap with the light emitting part extending forwardlyof the housing sleeve front end, said housing sleeve portion havinglaterally spaced fingers extending rearwardly of said cartridge,terminating in a dual lead support rear cartridge portion, at least oneballast resistor disposed in said housing at a region between saidspaced fingers, a pair of stiff wire leads extending longitudinally ofsaid cartridge, supported in said rear cartridge support portion andextending rearwardly straight from said cartridge, said stiff wire leadsbeing electrically connected through at least one ballast resistor tosaid diode, said housing outer surface being cylindrical and dimensionedto be insertable as a plug in a signal panel aperture and said stiffleads cooperating with contact blades of a signal panel mounted jack,each diode unit being exposed to atmosphere in front of the panel andlongitudinally spaced from a ballast, the ballast being located beyondthe rear face of a signal panel, whereby an array of lamp cartridgeplugs will have ballast resistors freely accessible to open air in therear of said signal panel for heat dissipation and individual cartridgesmay be removed or replaced in case of failure or change in operatingconditions.

1. A lamp cartridge plug for switchboards comprising a light emittingdiode having a pair of leads, an insulating cap for supporting saiddiode, said cap being sleeve-shaped with a light emitting part of saiddiode disposed at a front cap end for external viewing, said diode leadsextending from the rear cap end, a cartridge housing of molded,non-metallic material, said housing having a front sleeve portiondisposed about the cap with the light emitting part extending forwardlyof the housing sleeve front end, said housing sleeve portion havinglaterally spaced fingers extending rearwardly of said cartridge,terminating in a dual lead support rear cartridge portion, at least oneballast resistor disposed in said housing at a region between saidspaced fingers, a pair of stiff wire leads extending longitudinally ofsaid cartridge, supported in said rear cartridge support portion andextending rearwardly straight from said cartridge, said stiff wire leadsbeing electrically connected through at least one ballast resistor tosaid diode, said housing outer surface being cylindrical and dimensionedto be insertable as a plug in a signal panel aperture and said stiffleads cooperating with contact blades of a signal panel mounted jack,each diode unit being exposed to atmosphere in front of the panel andlongitudinally spaced from a ballast, the ballast being located beyondthe rear face of a signal panel, whereby an array of lamp cartridgeplugs will have ballast resistors freely accessible to open air in therear of said signal panel for heat dissipation and individual cartridgesmay be removed or replaced in case of failure or change in operatingconditions.